Efecto in vitro de 2 compuestos bioactivos, el ácido gálico y el galato de metilo, sobre la urolitiasis / In vitro effects of 2 bioactive compounds, gallic acid and methyl gallate, on urolithiasis

Introducción y objetivos: El objetivo de este estudio fue evaluar el papel de 2 compuestos fenólicos naturales ampliamente distribuidos, el ácido gálico (AG) y el galato de metilo (GM), en un modelo in vitro de urolitiasis, utilizando la metodología de formación de cristales de oxalato de calcio, el tipo más común de cálculos urinarios o renales.Material y métodosLos compuestos AG y GM fueron sometidos a actividades de «anticristalización» en diferentes concentraciones (0,003-0,03mg/mL), y la cantidad y morfología de los cristales se determinó por microscopia después de 60min.ResultadosEl AG inhibió alrededor del 44-57% de la formación total de cristales de cristales de oxalato de calcio, mientras que el GM inhibió alrededor del 48,35%, en comparación con las muestras expuestas al vehículo (agua destilada; grupo de control negativo). La exposición a AG y GM inhibió la formación de cálculos de tipo monohidrato, considerada la categoría de cristales más común y dañina. Los compuestos también disminuyeron la absorbancia, lo que a su vez está relacionado con una reducción de la agregación y precipitación de cristales de oxalato de calcio.ConclusionesEn conjunto, este estudio muestra, por primera vez, que el AG y el GM son compuestos prometedores con propiedades antiurolitiásicas, brindando nuevas perspectivas para futuros estudios in vivo del potencial de estos compuestos en el tratamiento y/o prevención de los cálculos urinarios o renales. (AU)

Introduction and objectives: This study aimed to evaluate the role of 2 widely distributed natural phenolic compounds, gallic acid (GA) and methyl gallate (MG), in an in vitro model of urolithiasis, by using the methodology of calcium oxalate crystals formation, which is the most common type of urinary or kidney stones.Material and methodsThe compounds GA and MG were subjected to anti-crystallization activities in different concentrations (0.003-0.03mg/mL), and the quantity and morphology of crystals were determined by microscopy after 60min.ResultsGA inhibited about 44-57% of the total calcium oxalate crystals formation, while MG inhibited about 48.35%, when compared to vehicle-exposed samples (distilled water; negative control group). GA and MG exposure inhibited monohydrate type calculi formation, which is considered the most common and harmful crystal category. The compounds also decreased absorbance, which in turn is related to reduced calcium oxalate crystals aggregation and precipitation.ConclusionsAltogether, this study shows, for the first time, that GA and MG are promising compounds with antiurolithiatic properties, opening new perspectives for future in vivo evaluations of the potential of these compounds in the treatment and/or prevention of urinary or kidney stones. (AU)

In vitro effects of two bioactive compounds, gallic acid and methyl gallate, on urolithiasis.

INTRODUCTION AND OBJECTIVES: This study aimed to evaluate the role of two widely distributed natural phenolic compounds, gallic acid (GA) and methyl gallate (MG), in an in vitro model of urolithiasis, by using the methodology of calcium oxalate (CaOx) crystals formation, which is the most common type of urinary or kidney stones. MATERIAL AND METHODS: The compounds GA and MG were subjected to anti-crystallization activities in different concentrations (0.003-0.03 mg/mL), and the quantity and morphology of crystals were determined by microscopy after 60 min. RESULTS: GA inhibited about 44-57% of the total CaOx crystals formation, while MG inhibited about 48.35%, when compared to vehicle-exposed samples (distilled water; negative control group). GA and MG exposure inhibited monohydrate type calculi formation, which is considered the most common and harmful crystal category. The compounds also decreased absorbance, which in turn is related to reduced CaOx aggregation and precipitation. CONCLUSIONS: Altogether, this study shows, for the first time, that GA and MG are promising compounds with antiurolithiatic properties, opening new perspectives for future in vivo evaluations of the potential of these compounds in the treatment and/or prevention of urinary or kidney stones.

In vitro effects of 2 bioactive compounds, gallic acid and methyl gallate, on urolithiasis. / Efecto in vitro de 2 compuestos bioactivos, el ácido gálico y el galato de metilo, sobre la urolitiasis.

INTRODUCTION AND OBJECTIVES: This study aimed to evaluate the role of 2 widely distributed natural phenolic compounds, gallic acid (GA) and methyl gallate (MG), in an in vitro model of urolithiasis, by using the methodology of calcium oxalate crystals formation, which is the most common type of urinary or kidney stones. MATERIAL AND METHODS: The compounds GA and MG were subjected to anti-crystallization activities in different concentrations (0.003-0.03mg/mL), and the quantity and morphology of crystals were determined by microscopy after 60min. RESULTS: GA inhibited about 44-57% of the total calcium oxalate crystals formation, while MG inhibited about 48.35%, when compared to vehicle-exposed samples (distilled water; negative control group). GA and MG exposure inhibited monohydrate type calculi formation, which is considered the most common and harmful crystal category. The compounds also decreased absorbance, which in turn is related to reduced calcium oxalate crystals aggregation and precipitation. CONCLUSIONS: Altogether, this study shows, for the first time, that GA and MG are promising compounds with antiurolithiatic properties, opening new perspectives for future in vivo evaluations of the potential of these compounds in the treatment and/or prevention of urinary or kidney stones.

Microscopic diagnosis of the leaf and stem of Piper solmsianum C.DC.

Piper solmsianum C.DC., which is popularly known as pariparoba, is a shrub that measures 1-3 m in height and it inhabits areas with wet tropical soils. The objective of this study was to analyze the leaf and stem anatomy using light microscopy, scanning electron micrographs, and energy-dispersive X-ray spectroscopy in order to provide information for species identification. The anatomical profile showed the following main microscopic markers: hypostomatic leaf; hypodermis layer on both sides; pearl glands; biconvex midrib shape; five collateral vascular bundles in open arc with the central bundle larger than the others; circular stem shape; collateral vascular bundles arranged in two rings; sinuous sclerenchymatic sheath in the pith; secretory idioblasts; and starch grains in the mesophyll, in the ground parenchyma of the midrib, petiole, and in the stem; and six morphotypes of calcium oxalate crystals (styloids, cuneiform, tabular crystal rosettes, cuneiform crystal rosettes, elongated square dipyramids, as well as very elongated square dipyramids).

Evidences of antihypertensive potential of extract from Solanum capsicoides All. in spontaneously hypertensive rats.

BACKGROUND: Solanum capsicoides All. is morphologically similar to Solanum sisymbriifolium Lam. which is used in folk medicine in South America for antihypertensive and diuretics purposes. This similarity has led to species identification errors, which therefore may result in errors by patients. PURPOSE: To evaluate the antihypertensive and diuretics potential of the methanol extract from Solanum capsicoides All. (MeOH-Sc), in vitro and in vivo, in spontaneously hypertensive rats (SHR). METHODS: Initial experiments were performed in rat mesenteric artery to evaluate the in vitro vascular effect of MeOH-Sc and its fractions, in addition to the mechanisms involved during the observed effect. Mean arterial pressure (MAP) and heart rate (HR) were recorded in non-anesthetised hypertensive and normotensive rats. In another set of experiments, MeOH-Sc was administered for 21 consecutive days. Daily body weight measurements were conducted and MAP, HR and urinary volume were measured every 5 days. The mesenteric artery from treated animals was tested for phenylephrine and sodium nitroprussiate (SNP) sensitivity. RESULTS: Initially, MeOH-Sc and fractions relaxed phenylephrine-induced contractions in mesenteric artery rings. The vasorelaxant effect was not changed in the presence of a blocker of eNOS (L-NAME) in rings with an intact endothelium. In denuded-endothelium rings, the vasorelaxant response was significantly reduced in the presence of a cAMP inhibitor (SQ 22536 10 µM) in SHR but not in Wistar Kyoto rats (WKY). However, in the presence of a cGMP inhibitor (ODQ 10 µM), a curve shift to the right was observed in WKY animals, but not in SHR. Intravenous bolus injections of MeOH-Sc into non-anesthetised SHR and WKY, induced hypotension that was associated with an increase in HR. A significant antihypertensive effect was observed in animals that received MeOH-Sc orally for 21 days, which also prevented the development of cardiac hypertrophy. Urine volume from animals treated with MeOH-Sc significantly increased. Finally, MeOH-Sc induced beneficial changes in vascular responsiveness. CONCLUSION: MeOH-Sc has a potential antihypertensive effect in SHR.

Chemical composition and in vitro antioxidant activity of hydro-ethanolic extracts from Bauhinia forficata subsp. pruinosa and B. variegata.

Bauhinia species are known to have hypoglycemiant and antioxidant activities. Here, hydro-ethanolic leaf extracts from Bauhinia forficata subsp. pruinosa and Bauhinia variegata, collected in a Pampa biome region of Brazil, were investigated to characterize their chromatographic profile, flavonoid content and in vitro antioxidant activity (TBARS and DPH assays). The extracts were obtained from dried and fresh leaves. The total flavonoid content was assessed by spectrophotometric determination, and the results ranged between 572.08 and 1,102.99 µg mL-1. Moreover, flavonoids were more predominant in B. variegata than in B. forficata subsp. pruinosa. HPLC analysis detected a complex profile of phenolic compounds, being the flavonoid kaempferitrin founded B. forficata subsp. pruinosa; in addition, other kaempferol and quercetin derivatives were present. In vitro antioxidant assays demonstrated a different behavior depending on the species, leaf treatment and extract concentration. In general, B. variegata extracts obtained from fresh material presented higher antioxidant potential, which can be attributed to the predominance of flavonoids in their chemical composition.

Antimicrobial and cytotoxicity potential of acetamido, amino and nitrochalcones.

Chalcones constitute one of the major classes of natural products belonging to the flavonoid family, and they have been reported as having a range of important therapeutic activities, including some chalcones are effective as antimicrobial agents. Currently, the search for new structures with antimicrobial activity has been intensified due to the emergence of many strains resistant to antibiotics currently used to treat infectious diseases.3 chalcone series (amino, acetamido and nitrochalcones) were prepared (23 compounds) and evaluated for their antimicrobial and cytotoxic potential. The effects of substituents on their respective activities also was evaluated.The results showed that 4 aminochalcones (2, 4, 8, 9), 3 acetoamidochalcones (10, 14, 18) and 3 nitrochalcones (20, 22, 23), exhibited antifungal effects. The aminochalcones were more toxic than the acetamidochalcones, while the nitrochalcones did not present any toxic effect. It was verified that there seems to be structure-activity correlation in some electron-donating and withdrawing substituents groups in rings A and B of the synthetized chalcone analogues and its antifungal and cytotoxic activity.

Antifungal, cytotoxic and SAR studies of a series of N-alkyl, N-aryl and N-alkylphenyl-1,4-pyrrolediones and related compounds.

The synthesis, in vitro evaluation and SAR studies of 67 maleimides and derivatives acting as antifungal agents are reported. A detailed SAR study supported by theoretical calculations led us to determine that: an intact maleimido ring appears to be necessary for a strong antifungal activity, dissimilarly affected by the substituents in positions 2 and 3. The best activities were shown by 2,3-nonsubstituted followed by 2,3 dichloro- and 2-methyl-substituted maleimides. They all were fungicide rather than fungistatic enhancing the importance of their antifungal activity. 2,3-Dimethyl and 2,3-diphenyl-maleimides possessed marginal or null activity. The presence of a flexible connecting chain in N-phenylalkyl maleimides appears not to be essential for antifungal activity, although its length shows a correlation with the antifungal behavior, displaying maleimides with alkyl chains of n=3 and n=4 the best antifungal activities in most fungi. Different substituents on the benzene ring did not have a clear influence on the activity. Values of chemical potential properties as well as of energy do not sufficiently discriminate between active and inactive compounds. Nevertheless, it was found that, although logP alone is not strong enough to properly predict the antifungal activity, the comparison of its values for compounds within the same sub-type, showed an enhancement of antifungal activity along with an increment of lipophilicity. In addition, the LUMO's electronic clouds of the highly active compounds showed to be concentrated on the imido ring, indicating that their carbon atoms are potential sites for nucleophilic attack. Same results were obtained from MEPs. Most of the active compounds did not show cytotoxic activity against human cancer cell lines and no one possessed hemolytic activity, indicating that their activity is selective to pathogenic fungi and that they are not toxic at MIC concentrations.

Evaluation of antinociceptive effects of Galipea longiflora alkaloid extract and major alkaloid 2-phenylquinoline.

The present study evaluated the antinociceptive properties of an alkaloid extract and 2-phenylquinoline obtained from the bark of Galipea longiflora Krause (Rutaceae) against different models of pain in mice. The results demonstrate that the alkaloid extract caused a pronounced antinociceptive effect with the main alkaloid detected, 2-phenylquinoline, exhibiting moderate activity. The alkaloid extract had a calculated ID50 value of 20.3 mg/kg i.p. and less than 50 mg/kg p.o. against the writhing test which proved to be more effective than the reference drugs when administered by both routes. The ID50 of 2-phenylquinoline was 52.8 mg/kg i.p. with an inhibition of 24.5% when administered orally at 100 mg/kg. In the formalin test the alkaloid extract, but not 2-phenylquinoline, significantly inhibited both phases of pain (neurogenic and inflammatory) at 10 mg/kg i.p. with inhibitions of 37.4% and 58.3%, respectively. The alkaloid extract and 2-phenylquinoline caused only a modest effect in the capsaicin and glutamate tests. In the hot plate test, the alkaloid extract increased the latency time by 25.6% at 10 mg/kg i.p. compared to 2-phenylquinoline which was less effective. It appears that the antinociceptive effects of this plant may be attributed, at least in part, to the presence of some antinociceptive alkaloids in minor concentrations.

Filicene obtained from Adiantum cuneatum interacts with the cholinergic, dopaminergic, glutamatergic, GABAergic, and tachykinergic systems to exert antinociceptive effect in mice.

In the present study, we describe the antinociceptive effect of filicene, a triterpene isolated from Adiantum cuneatum (Adiantaceae) leaves, in several models of pain in mice. When evaluated against acetic acid-induced abdominal constrictions, filicene (10, 30 and 60 mg/kg, i.p.) produced dose-related inhibition of the number of constrictions, being several times more potent [ID(50)=9.17 (6.27-13.18) mg/kg] than acetaminophen [ID(50)=18.8 (15.7-22.6) mg/kg], diclofenac [ID(50)=12.1(9.40-15.6) mg/kg] and acetylsalicylic acid [ID(50)=24.0(13.1-43.8) mg/kg] in the same doses as those used for the standard drugs. Filicene also produced dose-related inhibition of the pain caused by capsaicin and glutamate, with mean ID(50) values of 11.7 (8.51-16.0) mg/kg and <10 mg/kg, respectively. Its antinociceptive action was significantly reversed by atropine, haloperidol, GABA(A) and GABA(B) antagonists (bicuculline and phaclofen, respectively), but was not affected by L-arginine-nitric oxide, serotonin, adrenergic and the opioid systems. Together, these results indicate that the mechanisms involved in its action are not completely understood, but seem to involve interaction with the cholinergic, dopaminergic, glutamatergic, GABAergic and tachykinergic systems.

Toxicological and phytochemical studies of Aspidosperma subincanum Mart. stem bark (Guatambu).

Aspidosperma subincanum Mart. is widely used in Brazilian folk medicine to treat digestive disorders. In this study, acute and subchronic toxicity and cytotoxicity of stem bark ethanolic extract of Aspidosperma subincanum (EEAs) have been evaluated. In addition, phytochemical analysis was performed. The EEAs had low acute toxicity in mice with LD50 =1129 +/- 154mg/kg p.o. and 397 +/- 15 mg/kg i.p. The LC50 was 1340 +/- 428 microg/mL in the brine shrimp assay. There was no relevance of serious changes in behavioral, hematological and biochemical parameters and no deleterious effect on vital organs of rats that resulted after 30 days daily exposure to 5 and 100 mg/kg of EEAs. Phytochemical analysis of stem bark of A. subincanum revealed the presence of indole alkaloids, saponins, terpenoids, steroids and tannins and resulted in the isolation of oleic acid and guatambuine as major constituents. Using the method of the dose by factor approach, the human safe dose was 210 mg/70 kg/day. The EEAs appears to be safe and non-toxic in low doses in rodents and domestic preparations used by population have relatively security.

Analgesic properties of extracts and fractions from Erythrina crista-galli (Fabaceae) leaves.

The present study describes the analgesic activity of extracts and some fractions obtained from Erythrina crista-galli leaves in different in vivo analgesic models, using mice as experimental animals. The results showed that extract E(2) was the most active, inhibiting 48% of the abdominal constrictions when evaluated against the writhing test at 10 mg kg(-1), intraperitoneal. It also caused dose-dependent inhibition in the same model, with a calculated ID(50) value and respective confidence interval of 10 (9-14) mg kg(-1), and was more potent than reference drugs. Administered orally, E(2) caused potent antinociceptive action, with a calculated ID(50) value of 35 (26-47) mg kg(-1). The fractions F(1) and F(2) obtained from E(2) were evaluated against the writhing test at 10 mg kg(-1), causing inhibitions of 41 and 88%, respectively. The most active fraction, F(2), presented ID(50) calculated value of 3 (2-4) mg kg(-1), being about 7-fold more active than the reference drugs (acetyl salicylic acid and acetaminophen). In the formalin test, F(2) inhibited both phases of pain (44%, first phase; 58%, second phase). However, in contrast to the results observed for E(2), it was not active against the hot-plate test. The phytochemical results showed that at least four main components are present in F(2), which show a positive reaction of terpenes with TLC spray reagents.

The use of chitosan modified with glutaraldehyde and glyoxal as chromatographic support for the separation of flavonoids from Aleurites moluccana leaves.

This paper describes the preparation of chitosan modified with dialdehydes, glutaraldehyde (CH-Glu) and glyoxal (CH-Gly) and its application in the isolation of the flavonoids swertisin and 2"-O-rhamnosylswertisin from A. mollucana. The additional non-polar alkyl groups increase the hydrophobicity of the sorbent. The results show that the separation was mediated by hydrophobic interaction (CH-Glu), as well as hydrogen bonding, between phenolic OH or rhamnosil residues from the flavonoids, and the free amine groups (CH-Gly).

Analgesic potential of marrubiin derivatives, a bioactive diterpene present in Marrubium vulgare (Lamiaceae).

Marrubiin, a furane labdane diterpene, is the main analgesic compound present in Marrubium vulgare, a medicinal plant used in Brazil and other countries to treat several ailments. Considering its important pharmacological action, as well as its high yield, some structural modifications were performed in order to obtain more active compounds. Success was obtained in reducing the lactonic function, in the formation of marrubiinic acid and two esterified derivatives, which exhibited significant analgesic effect against the writhing test in mice. Marrubiinic acid showed better activity and excellent yield, and its analgesic effect was confirmed in other experimental models of pain in mice, suggesting its possible use as a model to obtain new and potent analgesic agents.

In vitro antifungal activity of dragon's blood from Croton urucurana against dermatophytes.

Based on ethnobotanical approach, the dragon's blood collected from Croton urucurana Baill. bark (Euphorbiaceae) was tested for antifungal activity against five dermatophytes by paper disk diffusion method. The minimal inhibitory concentration (MIC) showing no visible fungal growth was also determined, using tube dilution technique. The test dermatophytes were Tricophyton tonsurans, Trichophyton mentagrophytes, Trichophyton rubrum, Microsporum canis and Epidermophyton floccossum. The dragon's blood (0.175-3.0 mg/ml) exhibited an inhibition zone range of 7.6-26.9 mm against all the tested fungi with minimal inhibitory concentrations of 1.25-2.5 mg/ml.

Pharmacological and phytochemical investigations of different parts of Calophyllum brasiliense (Clusiaceae).

Continuing our search for antinociceptive agents from natural sources, this study analyzed the antinociceptive effects of some fractions obtained from different parts (roots, flowers and fruits) of Calophyllum brasiliense, a Brazilian medicinal plant used to treat several diseases, including inflammation and pain. For this purpose, the writhing and formalin induced-pain models in mice were used. We also analyzed the chemical composition of these different parts and tested two pure compounds isolated from chloroform fraction (roots) identified as friedelin (1) and 1,5-dihydroxyxanthone (3), by direct comparison with authentic samples. The results showed that some fractions and both compounds exhibited considerable antinociception properties, particularly against the writhing test, and that these are more potent than acetyl salicylic acid and acetaminophen, two reference drugs used here for comparison.

Isolation of flavonoids from Aleurites moluccana using chitosan modified with benzaldehyde (CH-Bz) as chromatographic support.

This paper describes the preparation, characterization and use of a derivative of chitosan as a chromatographic sorbent. Chitosan modified with benzenic ring (CH-Bz) was used to separate two flavonoids, swertisin and 2"-O-rhamnosylswertisin, from ethyl acetate fraction of Aleurites moluccana. The results showed that CH-Bz can be used as a sorbent for the separation of flavonoid compounds. The studies showed that CH-Bz in column chromatography produces goods results, separation of the flavonoid compounds.

Antifungal properties of novel N- and alpha,beta-substituted succinimides against dermatophytes.

The synthesis and antifungal properties of a series of new N-aryl alpha,beta-substituted succinimides against a panel of dermatophytes of clinical relevance are reported. Among those compounds possessing a N-phenyl substituent, 7-thia-2-azabicyclo[2,2,1]hept-2-en-3-amine[5,6-c]succinimide was the better inhibitor of Trichophyton rubrum, the major ethiological agent of all infections produced by dermatophytes. In contrast, succinimides containing a N-(p-sulfonylphenyl) substituent, only inhibited Epidermophyton floccosum, all active compounds possessing an oxabicyclo group in positions alpha,beta of the imide. Substituents on the oxabicyclo group were important for the activity. Regarding the mechanism of action, N-(p-N'-4-methoxyphenylsulfamoylphenyl)-8-oxabicyclo[2,2,1]hept-4-en-3- methyl[5,6-c]succinimide produced a mottled inhibition halo in the Neurospora crassa assay, showing that it would act by inhibiting the synthesis or assembly of the fungal cell wall.

Antinociceptive action of extracts and fractions from Rubus imperialis (Rosaceae).

Rubus imperialis is a Brasilian medicinal plant which previously exhibited therapeutical perspectives. This work describes the antinociceptive action of methanolic extracts obtained from different parts of the plant (roots and branches) as well as hexane, chloroform and ethyl acetate fractions obtained from branches. Such extracts or fractions caused significative inhibition in the writhing test in mice at 10 mg/kg, given intraperitoneally. They were more active than two reference drugs, aspirin and paracetamol. The fractions also exhibited antinociceptive activity in the writhing test when administered orally at 200 mg/kg. When analyzed in the formalin test, the chloroform fraction was the most active, causing considerable inhibition against both neurogenic and inflammatory phases of pain.

Hypolipidaemic activity of methanol extract of Aleurites moluccana.

The lipid-lowering action of the leaves of the Aleurites moluccana methanol extract was studied in Triton W-1339 and high-fat-diet fed rats. The serum lipids (total cholesterol, LDL- and HDL-cholesterol and triglycerides) and body weight were found to be lowered by A. moluccana (300 mg/kg, b.w.) in rats with Triton-induced hypercholesterolaemia and on a hyperlipaemic diet. The results suggest that the lipid lowering action of this natural product is mediated through inhibition of hepatic cholesterol biosynthesis and reduction of lipid absorption in the intestine.